Our verdict is Uncertain significance. Variant got 5 ACMG points: 6P and 1B. PM2PM5PP3_ModerateBP6
The NM_000249.4(MLH1):āc.650G>Cā(p.Arg217Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,558 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R217G) has been classified as Likely benign.
MLH1 (HGNC:7127): (mutL homolog 1) The protein encoded by this gene can heterodimerize with mismatch repair endonuclease PMS2 to form MutL alpha, part of the DNA mismatch repair system. When MutL alpha is bound by MutS beta and some accessory proteins, the PMS2 subunit of MutL alpha introduces a single-strand break near DNA mismatches, providing an entry point for exonuclease degradation. The encoded protein is also involved in DNA damage signaling and can heterodimerize with DNA mismatch repair protein MLH3 to form MutL gamma, which is involved in meiosis. This gene was identified as a locus frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). [provided by RefSeq, Aug 2017]
Verdict is Uncertain_significance. Variant got 5 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr3-37012071-C-T is described in Lovd as [Pathogenic].
PP3
MetaRNN computational evidence supports a deleterious effect, 0.886
BP6
Variant 3-37012072-G-C is Benign according to our data. Variant chr3-37012072-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 629885.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.